AB stands for adult baby while DL stands for diaper lover.
Adult babies are adults who enjoy regressing to a younger age (usally between the ages of 0 months and 7 years). Most ABs
will wear diapers and some
will wet or even soil them. They may enjoy wearing adult sized baby clothes, playing with baby toys, watching cartoons, being bottle or breast fed, sleeping in a crib, eating from a high chair, and doing other baby activities. Some are lucky enough to find an adult partner who
will take on the role of a caretaker (babysitter,
mother,
father,
sister,
brother, etc.). This person might
change, feed, play with, dress, or altogether care for the adult baby. The caretaker usually gets great satisfaction out of caring for another person, having the AB be dependent on them, or being in control. The AB most often gets satisfaction from the
safe and secure feeling they get from regressing. They may also like the idea of being able to regain that childhood innocence and joy. Generally there is no sexual motivation behind the desire to be an AB, especially for women. This would not make it a fetish.
A diaper lover, as the
name implies, enjoys wearing diapers. Some
will wet or soil their diapers. Some like to be changed by others. Some just enjoy seeing others in diapers. In my experience, I have found that there is almost always a sexual motivation behind being a DL. This is more closely related to a fetish.
I would like to make it clear that this has nothing to do with actual children or pedophilia. This is a common misconception. AB/DLs simply enjoy regressing to a younger age and/or wearing diapers.